The B-29 (also called Superfortress) was a four-engine heavy bomber that was built by Boeing. It was first flown in 1942 and soon became popular in the Pacific theatre during World War II. In 1944 the B-29 was selected to carry the atomic bomb, and a number of the aircrafts subsequently underwent various modifications, such as reinforcements of the bomb bay. That year Lieutenant Colonel Tibbets, who was one of the most experienced B-29 pilots, was tasked with assembling and training a crew. The modified B-29s were later flown to the U.S. military base on Tinian, one of the Mariana Islands.

U.S. bomber Enola Gay on Tinian, Mariana Islands, prior to its atomic bombing mission to Hiroshima, Japan, August 1945.Air Force Historical Research Agency

On July 16, 1945, the United States successfully tested an atomic bomb. Pres. Harry S. Truman was informed of the development while attending the Potsdam Conference, and he in turn told Soviet leader Joseph Stalin that the United States had “a new weapon of unusual destructive force.” On July 26 the Allied leaders called for Japan to unconditionally surrender or face “prompt and utter destruction.” After Japan ignored the demand, the decision was made to bomb Hiroshima.

At approximately 2:45 am on August 6, 1945, Tibbets—who was now a full colonel—and a crew of 11 took off from Tinian island carrying a uranium bomb that was known as “Little Boy.” The Enola Gay—Tibbets had a maintenance man paint that name on the aircraft’s nose shortly before takeoff—was accompanied by various other planes. At 8:15 am, the bomb was released over Hiroshima. While some 1,900 feet (580 feet) above the city, Little Boy exploded, killing tens of thousands and causing widespread destruction. Tibbets flew the Enola Gay back to Tinian, where he was awarded the Distinguished Service Cross. Three days later the Enola Gay conducted weather reconnaissance in the lead-up to the bombing of Nagasaki. Japan officially surrendered on September 2, 1945.

The B-29 Superfortress Enola Gay backed over a pit to be loaded with the first atomic bomb, which was released on Hiroshima, Japan, on Aug. 6, 1945.Air Force Historical Research Agency

B-29 Superfortress Enola GayThe B-29 Superfortress Enola Gay took off from the Mariana Islands on August 6, 1945, bound for Hiroshima, Japan—where, with the dropping of the atomic bomb, it heralded a new and terrible concept of warfare. From The Second World War: Allied Victory (1963), a documentary by Encyclopædia Britannica Educational Corporation.Encyclopædia Britannica, Inc.

The Enola Gay remained in service for several years before being given to the Smithsonian Institution on July 3, 1949. It was later disassembled and stored in Maryland. In 1984 work began on restoring the aircraft, which was in dire need of repair. Exposure to the elements had damaged the plane, and it had been vandalized. In addition, birds had built nests in various compartments. The project ultimately spanned some 20 years. In 1995 a portion of the plane served as the centerpiece of a controversial exhibition at the Smithsonian’s National Air and Space Museum (NASM) in Washington, D.C. The exhibit had originally been scheduled to include artifacts from Hiroshima and Nagasaki and highlight the debate over the decision to use the bomb. Amid fierce opposition, however, the original plans were canceled and a much scaled-back version was staged. In 2003 the fully restored Enola Gay was put on display at the NASM’s Steven F. Udar-Hazy Center in Chantilly, Virgina.